We usually mashup multiple RSS feeds using the amazing Yahoo Pipes, and then redirect them via Feedburner. But lately all our newly created Feedburner feeds were not updating.� Feedburner returned “Error getting URL: 999 – Unknown” with HTTP Error code 502, though the Yahoo! pipes source feed was valid RSS.

Possibly this has something to do with migration of Feedburner accounts to Google accounts and the recent redirects of feeds.feedburner urls to the new feeds2.feedburner urls which is causing duplicate feed issues with feedproxy.google urls.

All attempts to troubleshooting feedburner proved futile and even the last resort to Resync the feed was of no use. The Feedburner feed would simply not update. I hope Yahoo! who runs Pipes and Google who runs Feedburner sort out this feed communication / compatibility issue fast so that thousands of feeds are least affected and the readers stay subscribed.

If you recently created a new Feedburner feed which sources Yahoo Pipes, then you must check if it is working.

Update: Google has advised against moving your Feedburner feeds to Google accounts if the original source is Yahoo Pipes for now� -� “We are working directly with Yahoo! to restore Google-hosted feeds’ access to Pipes as soon as possible, but until this fix is in place, FeedBurner feeds with Pipes sources moved to Google will stop working properly.”

Update 2: Yahoo! has identified the cause and it should be fixed soon.

During this migration, the IPs used by Feedburners to access feeds have changed and we were not made aware of this change before it happened. As a result, Pipes has been blocking some of their new IP’s that came online. We have since added those IP’s to our whitelist and we are in the process of unblocking them.